Process to Control the Payload Temperature of a Shipping Container in Transit

ABSTRACT

A process with associated methods keeps the internal temperature of a cargo container within a temperature range during long transits having unpredictable high ambient temperatures. A cargo payload is shipped inside of an insulated container. The insulated container contains some form of refrigerant cooling agent (such as gel packs) to assist in keeping the internal temperature within the temperature range during transit. The container&#39;s shipping route to its destination includes stops at physical stations (hubs) where the container&#39;s internal temperature is measured using non-intrusive methods. If the internal temperature is above a trigger value, the container&#39;s refrigerant is replaced with new frozen ones. The container is shipped to the next hub or end destination. By exchanging refrigerant as needed, the container and its payload can traverse long distances over long time periods and still maintain its internal temperature within a desired window.

RELATED APPLICATION

This application is a non-provisional of U.S. Ser. No. 61/736,298, filed Dec. 12, 2012.

FIELD OF THE INVENTION

This invention relates to shipping systems, and more particularly to a method for maintaining a defined internal temperature range of a standalone, passive, shipping container over a long distance of transit.

BACKGROUND OF THE INVENTION

Hot and cold sensitive products such as payloads of food, medicine, or liquid are often shipped using some sort of ambient-temperature insulating container. Common payload insulators include polyurethane and expanded polystyrene. There are passive and active (usually battery powered) methods to control the internal temperature.

Insulation by itself may not keep the internal payload within a defined temperature range during transit when using passive containers. This is especially true when the shipped container experiences high ambient temperatures during a long passage. It is desired to maintain a container's internal payload temperature within a specified range over long distance travel using temperature management techniques along with passive packaging.

Passive ambient-temperature insulted shipping containers have been in existence for many decades. In general, there are several categories of temperature insulation techniques to maintain internal temperature stability for standalone containers. Examples of these are:

1. Ambient-temperature insulated container (such as a picnic cooler with walls of expanded polystyrene foam).

2. Ambient-temperature insulated container with dry ice, refrigerated gel packs, or other phase change material (such as a picnic cooler with frozen gel packs).

3. Ambient-temperature insulated container with active cooling and/or heating during transit. The internal temperature of the container is heated or cooled using energy from a battery supply or other internal or external energy source. An internal thermostat and controller maintain the container internal temperature.

Each choice above has associated pros and cons in terms of maintaining internal temperature stability. For example, in order of the list above,

1. Limited internal temperature stability when the ambient is very hot or cold. Even with three-inch thick insulated walls, the internal payload temperature may vary outside the desired range after only 8-12 hours of transit time.

2. This offers improved internal temperature stability compared to 1. Typically, 48-72 hours of transit are common even with ambient temperatures occasionally peaking 40F above the internal target temperature. Beyond about 3 days in transit, this solution performs poorly especially with wide dynamic-ranging ambient temperatures.

3. This method offers sustained internal temperature stability over long distance routes. The container requires an internal energy source and controller module to keep the payload within the desired temperature range. Solutions of this type are very expensive, heavy and large compared to methods 1 and 2. This is not practical for most shipping scenarios.

There is currently no practical way to ship containers over long distances (3K-12K miles) with transit times of up to 9 days and still maintain the payload temperature within a desired range. Some carriers offer 2-3 day shipping, using refrigerated containers, from any point to any point worldwide, but the costs are prohibitively high for many uses and applications.

What is desired is a shipping system that controls the temperature of a payload inside a shipping container. A passive shipping container that does not require an energy source to maintain temperature is desirable. A low-cost method to maintain a payload's temperature within a range despite long shipping distances and transit times is desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a basic flow and process steps for passive temperature-controlled transit.

FIG. 2 shows some components of one embodiment of a passive temperature-controlled shipping system.

FIG. 3 shows a process flow of a temperature-controlled shipping system.

DETAILED DESCRIPTION

The present invention relates to an improvement in passive temperature-controlled shipping. The following description is presented to enable one of ordinary skill in the art to make and use the invention as provided in the context of a particular application and its requirements. Various modifications to the preferred embodiment will be apparent to those with skill in the art, and the general principles defined herein may be applied to other embodiments. Therefore, the present invention is not intended to be limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features herein disclosed.

The inventors have developed a shipping system that monitors and controls the internal temperature of a container and its payload over long distance routes, with wide ambient temperature variations. The basic elements of the shipping system are:

An insulated container with an internal payload space. In practice, this is a small to moderate sized container that can be lifted by hand. This container is called the Temperature-Controlled Container (TCC). The payload is typically a second secure container that fits inside the main container (TCC), referred to as the Payload Container (PC).

Frozen gel packs (or dry ice or similar) are loaded inside the TCC to cool the payload inside and to absorb heat flux that enters through the TCC container's walls.

The entire end-to-end route is broken into shorter hops between physical hubs. Service personnel at each hub are able to check the temperature status of each package. Temperature is measured using non-intrusive methods at each hub. TCC or PC containers are not opened for measurement. They remain undisturbed.

If the measured internal temperature is above a trigger temperature, T_(trig), then the TCC container is opened and the gel packs (or other refrigerant) are replaced with fresh frozen gel packs or other refrigerant. The PC is never opened. This process occurs at each hub along the route.

The end customer receives the TCC and PC combination. The internal payload temperature always stays between T_(low) and T_(hi), thus meeting the requirements for long distance transits with controlled and stable payload temperatures.

FIG. 1 shows a basic flow and process steps for passive temperature-controlled transit. An example of the process is as follows:

At the origin, load the sealed PC with its cargo, load the PC inside of the TCC, and load gel packs or equivalent into the TCC and seal the TCC.

Ship to Hub_A (same country or different) with unpredictable ambient temperatures along the route.

On receipt of the TCC at Hub_A, measure the internal temperature without opening the container. This can be done using non-intrusive methods such as described later.

If the measured internal temperature, T_(meas), of the TCC is >T_(trig) then open the TCC, replace the gel packs (or equivalent refrigerants) with fresh ones, and close and reseal the TCC. A measured value below T_(trig) provides confidence that the TCC can make the next leg of the transit with the payload temperature <T_(hi) upon arrival at next stop.

Ship to the next Hub or destination location. If sent to another hub such as Hub_B, repeat same process as at Hub_A.

If the transit time between individual shipping points (origin, hubs, destination) is less than about 3 days then the internal TCC temperature can be maintained between T_(low) and t_(hi) along the entire route (up to 9 days with 2 hubs) from origin to destination given any required refrigerant recharges. These estimates are not fixed and longer transit times are possible with sufficient internal passive cooling and/or improved thermal insulation of the TCC.

One embodiment of this invention focuses on maintaining the payload temperature between a T_(low) at 35° F. and a T_(hi) at 70° F. Other, bounds are possible. One purpose of this shipping system is to protect the payload against long exposure times to high ambient temperatures (such as T_(ambient)>80° F.) during a transit.

FIG. 2 shows some components of one embodiment of the passive temperature-controlled shipping system. Cargo payload 201 may be any item(s), such as liquids, medical, pharmaceuticals, foods, or other items, that need shipping from a source to a destination under temperature-controlled conditions. In cases with a liquid cargo, the cargo may be pre-chilled to assist in the overall cooling of the shipping container's internal space. Cargo payload 201 is loaded into Payload Container (PC) 202 and secured such as by closing. This container may be locked or secured in any fashion and is typically never opened again except by the end-point receiving agent.

Next, PC 202 is loaded into Temperature Controlled Container (TCC) 203. Refrigerant 206 is also loaded into provided spaces inside TCC 203. The refrigerant is secure and confined to 2 or more sides of TCC 203. The exact number, placement, and location of the refrigerant may vary. However, the refrigerants should be placed such that a non-invasive temperature probe does not come into contact with refrigerants during measurement. So, typically, the refrigerants would be placed equally far apart from measurement location near door 204 so as not to bias the measurement. For example, if refrigerants are loaded along sides 1, 2 and 3 of TCC 203, then the non-invasive measurement could occur on side 4.

One aspect of TCC 203, not found on traditional insulated containers, is a small access port used to measure the internal temperature at the Hub. This port or door 204 may be cut into the corrugated top flap. Corrugated containers are not required but are one example embodiment. The top of the container is sealed with a flexible, inserted, insulated plug 205. Other plugs or equivalent means are possible, and this is not an essential part of the shipping system.

Once TCC 203 is loaded with PC 202 and refrigerants 206, it is ready to be shipped to the first hub. The Hub is a geographic location able to support the following:

1.) Shipping and receiving of TCCs 203

2.) A Freezer unit to freeze the refrigerants, typically gel packs

3.) Temperature probe 207 and temperature meter 208, used to measure the internal temperature of all received TCCs.

4.) Ability to open/reseal TCC 203 and replace its refrigerants with new frozen ones if the measured temperature is above a defined trigger point.

Measurement Method

It is important that the internal temperature is measured without disturbing the contents of the TCC. So, a non-intrusive technique to measure the internal temperature is desirable. Such a method includes the following steps:

Open the small, hinged monitor door 204 in the top corrugated flap.

Insert the long, thin probe 207 between insulated wall 210 and the side of the top plug, 205. See insert 209, shown with door 204 open. An 8-inch long probe, for example, is guided into the TCC to measure its quiescent temperature. The probe does not disturb the internal refrigerants or cargo. Meter 208 is allowed time to settle to a stable value before recording.

Once the temperature is recorded, the probe is removed and port door 204 is securely closed.

When using the probe method, the measured temperature, T_(meas), may be a predictable T_(offset) degrees higher than the actual payload cargo temperature, T_(payload). This may be because the inserted probe is not in direct contact with the cargo items inside the sealed PC. So T_(payload)=T_(meas)−T_(offset). Typically, T_(payload) load falls between the design limits T_(low) and T_(hi). The probe method may rely on this calibrated T_(offset) as part of the decision process of when to replace refrigerants. T_(offset) will typically be a small value ranging from near 0° F. to about 4° F. depending on PC material, cargo heat capacity, and other factors.

Process Flow

FIG. 3 shows a process flow of the temperature-controlled shipping system. The goal is to keep the Temperature Controlled Container (TCC) internal payload temperature within the bounds of T_(low) and T_(hi) during long transits with unpredictable high ambient temperatures.

The process starts with step 301, loading the Payload Container (PC) with the cargo payload. As an option, the payload may be pre-chilled before loading. For example, if the payload is bottled liquid it may be chilled to 50° F. before loading. The cooled liquid payload adds to the overall temperature stability inside the TCC during transit and reduces the need for additional loaded refrigerants.

Step 302 adds the frozen gel packs or other refrigerant into the TCC. The total weight of the refrigerant (cooling power) is related to the transit time to the next stop, the expected ambient temperatures on route and the insulation strength of the TCC. Step 303 ships the TCC to the first Hub using conventional land, air or sea transport methods.

At step 304, the TCC is received at the Hub. Before shipment to the next hub or destination, the internal temperature, T_(meas), is measured. The measurement method is described earlier.

At step 305, if T_(meas) is greater than a predefined T_(trig), then proceed to step 307. In step 307 the TCC is opened and the refrigerants removed and replaced with similar but frozen refrigerants. At step 308, the TCC is resealed and sent to the next hub or destination. The refrigerant recharge provides sufficient cooling power for the next leg of the transit. The Payload Container is not opened.

When the next hop is to another hub, step 310, then the process is repeated from step 304. When the next hop is the final destination, step 310, then in step 309 the payload cargo (PC) is removed from the TCC at the final destination.

At step 305, if T_(meas) is less than or equal to a predefined T_(trig), then the process proceeds to step 306. The refrigerants possess sufficient cooling power for the next leg of the transit. In step 306 the TCC is not opened and is sent to the next hub or destination.

When the next hop is to another hub, step 311, then the process is repeated from step 304. When the next hop is the final destination, step 311, then in step 309 the payload cargo (PC) is removed from the TCC at the final destination.

The hub processing loops (steps 305-307-308-310-304) or (steps 305-306-311-304) are executed as required until the entire procedure ends at step 309, the end of the shipping process.

ALTERNATE EMBODIMENTS

Several other embodiments are contemplated by the inventors. For example, there may be one hub or more than one hub. The payload container and temperature-controlled container may have various shapes and sizes and are not limited to boxes. They may be made from corrugated cardboard, wood, or from other materials. The PC and TCC could be made from different materials. For example, the PC could be a wood box containing wine bottles, while the TCC is a cardboard box.

While a single payload container has been described, each TCC could have more than one payload container. The number of gel packs could be increased, and various arrangements of gel packs may be used.

This temperature-controlled shipping system does not require the use of the probe method to determine T_(payload). There are other methods to non-intrusively measure the internal TCC temperature. One method is to place the active end of a thermocouple wire inside the TCC and thread the other end to the access port door 204. This method does not require a probe but relies on the thermocouple wire end point to measure the internal temperature. Another method relies on an inserted temperature monitor module that communicates wirelessly to an external recording device or meter. There are many methods to non-invasively measure the internal temperature of the TCC. The payload container may be temporarily removed from the TCC at the hub to allow a refrigerant pack placed underneath the payload container to be replaced at the hub.

An internal temperature sensor could have a radio or other transmitter to allow the temperature to be read wirelessly, such as by WiFi, Bluetooth, or Radio-Frequency Identification (RFID) where the ID is adjusted by the temperature sensor. An internal power source such as a small battery may be included for the radio transmitter, or power may be coupled into the internal temperature sensor inductively.

Mixed modes of transport may be used. For example, trucking may be used for one leg, while a cargo ship is used for another leg. Air may be used for other legs. One hop between hubs may include several modes of transport, such as a ship and local trucks. Standard tracking methods such as reading bar codes may be used at hubs to identify boxes for temperature-controlled processing, or the TCC could be addressed and delivered to a facility at each hub. A new shipping label could be affixed at each hub.

While upper and lower limit temperatures have been described, only an upper temperature limit may be used. Alternately, only a lower temperature limit may be used, such as to prevent damage due to extremely low temperatures in the unpressurized cargo holds of airplanes. The shipping system could be combined with other shipping systems and methods.

The trigger temperature could be the same at all hubs, or could be set to different temperatures at different hubs. Hubs before longer or slower transit links could have lower trigger temperatures to compensate for additional distances and expected heating. Trigger temperatures could also differ for different types or sizes/masses of payloads.

The background of the invention section may contain background information about the problem or environment of the invention rather than describe prior art by others. Thus inclusion of material in the background section is not an admission of prior art by the Applicant.

Any advantages and benefits described may not apply to all embodiments of the invention. When the word “means” is recited in a claim element, Applicant intends for the claim element to fall under 35 USC Sect. 112, paragraph 6. Often a label of one or more words precedes the word “means”. The word or words preceding the word “means” is a label intended to ease referencing of claim elements and is not intended to convey a structural limitation. Such means-plus-function claims are intended to cover not only the structures described herein for performing the function and their structural equivalents, but also equivalent structures. For example, although a nail and a screw have different structures, they are equivalent structures since they both perform the function of fastening. Claims that do not use the word “means” are not intended to fall under 35 USC Sect. 112, paragraph 6.

The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. 

We claim:
 1. A temperature-controlled shipping system comprising: a Temperature-Controlled Container (TCC) for maintaining a temperature of a payload being shipped from a shipping source to a destination through a hub; a payload container for holding the payload during shipment to the destination, the payload container being fitted inside the TCC at the shipping source and being removed from the TCC at the destination for delivery to a customer at the destination; a removable refrigerant inserted into the TCC at the shipping source, the removable refrigerant being pre-cooled to an initial temperature that is below a standard room temperature before insertion into the TCC; a temperature sensor, inserted into the TCC at the hub, or embedded inside the TCC and readable at the hub, for reading a temperature inside the TCC when the TCC is processed at the hub; and wherein a replacement refrigerant, pre-cooled at the hub, is inserted into the TCC at the hub to replace the removable refrigerant when the temperature inside the TCC exceeds a trigger temperature when read at the hub; wherein the removable refrigerant is not replaced and the TCC is not opened when the temperature inside the TCC does not exceed the trigger temperature when read at the hub, whereby the removable refrigerant is replaced by the replacement refrigerant at the hub when the temperature inside the TCC exceeds the trigger temperature when read at the hub.
 2. The temperature-controlled shipping system of claim 1 wherein the TCC has insulating exterior walls; wherein the removable refrigerant is a passive refrigerant that gradually absorbs heat that leaks into the TCC through the insulating exterior walls from an external ambient having a higher external ambient temperature than an internal temperature of the TCC.
 3. The temperature-controlled shipping system of claim 1 wherein a first transit time from the shipping source to the hub is at least 2 days, and wherein a second transit time from the hub to the destination is at least 2 days.
 4. The temperature-controlled shipping system of claim 1 further comprising: a door in the TCC, the door being opened at the hub, wherein an opening of the door is sized to allow a temperature probe to be inserted into the TCC at the hub, wherein a temperature-sensing tip of the temperature probe is inserted through the opening of the door into the TCC to measure the temperature inside the TCC at the hub.
 5. The temperature-controlled shipping system of claim 4 wherein the door is sufficiently large in size to insert the temperature probe, but not large enough for the payload container or the removable refrigerant to be removed.
 6. The temperature-controlled shipping system of claim 5 wherein the temperature probe is inserted between a wall of the TCC and the payload container, wherein the temperature probe measures a temperature inside the TCC and outside the payload container.
 7. The temperature-controlled shipping system of claim 3 wherein the removable refrigerant and the replacement refrigerant are one or more gel packs containing a gel refrigerant material, the gel packs being sized to be removable by a human hand; wherein the gel packs do not require an electrical energy source to provide cooling while the TCC is in transit.
 8. The temperature-controlled shipping system of claim 7 wherein the removable refrigerant has a sufficiently large thermal mass to maintain a temperature of the payload container below 70° F. during transit between the shipping source and the hub.
 9. The temperature-controlled shipping system of claim 7 wherein the removable refrigerant comprises three gel packs that are inserted into the TCC on three sides of the payload container; further comprising: a door for the temperature probe that is located near a fourth side of the payload container that does not have a gel pack.
 10. The temperature-controlled shipping system of claim 9 wherein the payload is one or more bottles of wine.
 11. The temperature-controlled shipping system of claim 3 wherein the payload is pre-cooled to a temperature below a standard room temperature before shipping.
 12. The temperature-controlled shipping system of claim 1 wherein the temperature sensor comprises an embedded temperature sensor embedded within the TCC; further comprising: a wireless transmitter inside the TCC for wirelessly transmitting a temperature read by the embedded temperature sensor to an external reader at the hub; wherein the TCC is not opened at the hub.
 13. The temperature-controlled shipping system of claim 1 further comprising a second hub which comprises: a temperature probe for reading a temperature inside a TCC received at the second hub during transit between the shipping source and the destination; a hub refrigerator for pre-cooling replacement refrigerants; an operator station for inserting the temperature probe into the TCC to measure an interior temperature of the TCC, and for opening the TCC and removing the removable refrigerant, and inserting the replacement refrigerant, pre-cooled at the second hub, into the TCC at the second hub to replace the removable refrigerant when the interior temperature inside the TCC exceeds a trigger temperature when read at the second hub; wherein the removable refrigerant is not replaced and the TCC is not opened when the interior temperature inside the TCC does not exceed the trigger temperature when read at the second hub, whereby the removable refrigerant is replaced by the replacement refrigerant at the second hub when the interior temperature inside the TCC exceeds the trigger temperature when read at the second hub.
 14. A method for controlling in-transit temperature of a payload being shipped from a shipping source to a destination comprising: loading a payload into a payload container for shipment; loading the payload container with the payload into a Temperature-Controlled Container (TCC); inserting a pre-cooled refrigerant pack into the TCC; sealing the TCC with the pre-cooled refrigerant pack and the payload container inside as a sealed TCC; shipping the sealed TCC from the shipping source to a first hub; at the first hub, reading a first interior temperature inside the TCC without removing the payload container and without exposing the payload container to an ambient temperature; at the first hub, when the first interior temperature exceeds a first trigger temperature, opening the TCC and exposing the payload container to the ambient temperature, removing the refrigerant pack inside the TCC with a pre-cooled refrigerant pack that was pre-cooled at the first hub, and re-sealing the TCC with the pre-cooled refrigerant pack that was pre-cooled at the first hub; shipping the TCC that was re-sealed at the first hub, or had a first interior temperature below the first trigger temperature and was not opened, from the first hub to a destination or to a second hub; and at the destination, removing the payload container from the TCC and delivering the payload container to a customer.
 15. The method of claim 14 further comprising: at the second hub, reading a second interior temperature inside the TCC without removing the payload container and without exposing the payload container to an ambient temperature; at the second hub, when the second interior temperature exceeds a second trigger temperature, opening the TCC and exposing the payload container to the ambient temperature, removing the refrigerant pack inside the TCC and replacing with a pre-cooled refrigerant pack that was pre-cooled at the second hub, and re-sealing the TCC with the pre-cooled refrigerant pack that was pre-cooled at the second hub; and shipping the TCC that was re-sealed at the second hub, or had a second interior temperature below the second trigger temperature and was not opened, from the second hub to the destination or to a third hub.
 16. The method of claim 14 wherein the shipping source and the destination are on different continents.
 17. The method of claim 14 wherein at the first hub, reading a first interior temperature inside the TCC comprises: opening a door on the TCC, inserting a temperature probe through an opening of the door so that a temperature-reading tip of the temperature probe is inside the TCC, removing the temperature probe, and closing the door; wherein the opening of the door is sufficiently small relative to a size of the TCC to not allow all air within the TCC to be replaced with ambient air during temperature measurement.
 18. The method of claim 14 wherein loading the payload into the payload container for shipment comprises loading a bottle of wine into the payload container.
 19. The method of claim 14 wherein loading the payload into the payload container for shipment further comprises pre-cooling a bottle of wine and loading a pre-cooled bottle of wine into the payload container.
 20. A conditional in-transit refrigerant-repacking system comprising: at an intermediate hub along a shipping route from a source to a destination that receives a Temperature-Controlled Container (TCC) having a payload container and a removable refrigerant sealed inside: non-intrusive temperature reading means for reading an interior temperature inside the TCC without removing the payload container and without heating the payload container with an ambient temperature; re-pack means, activated when the interior temperature exceeds a trigger temperature, for opening the TCC and exposing the payload container to the ambient temperature, for removing the refrigerant pack inside the TCC and replacing with a pre-cooled refrigerant pack that was pre-cooled at the intermediate hub, and for re-sealing the TCC with the pre-cooled refrigerant pack that was pre-cooled at the intermediate hub; and re-ship means for shipping the TCC that was re-sealed at the intermediate hub, or had an interior temperature below the trigger temperature and was not opened, from the intermediate hub to the destination or to another intermediate hub.
 21. The conditional in-transit refrigerant-repacking system of claim 20 further comprising: port means for opening a door on the TCC, inserting a temperature probe through an opening of the door so that a temperature-reading tip of the temperature probe is inside the TCC, recording the interior temperature read by the temperature probe, removing the temperature probe, and closing the door; wherein the door is sufficiently large in size to insert the temperature probe, but not large enough for the payload container or the removable refrigerant to be removed. 